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TN19 121211-20
Creosote
Formation and Need for Removal
When wood is burned slowly, it produces tar and other
organic vapours, which combine with expelled moisture
to form creosote. The creosote vapours condense in the
relatively cool chimney fl ue of a slow burning fi re. As a
result, creosote residue accumulates on the fl ue lining.
When ignited, this creosote makes an extremely hot fi re.
The chimney connector and chimney should be inspected
periodically (at least once every two months) during the
heating season to determine if a creosote buildup has
occurred. If creosote has accumulated (3 mm. or more), it
should be removed to reduce the risk of a chimney fi re.
1. Highest smoke densities occur when a large amount
of wood is added to a bed of hot coals and the air inlet is
closed. The heated wood generates smoke, but without
ample air, the smoke cannot burn. Smoke-free, clean
burning requires small fuel loads, two or three logs at
a time or 1/4 to 1/2 of fuel load and leaving the air inlet
relatively wide open, especially during the fi rst 10 to 30
minutes after each loading, when most of the smoke
generating reactions are occurring. After 30 minutes or
so, the air inlet can be turned down substantially without
excessive smoke generation. Wood coals create very
little creosote-producing smoke.
2. The cooler the surface over which the wood smoke is
passing, the more creosote will be condensed. Wet or
green wood contributes signifi cantly to creosote formation
as the excess moisture that is boiled off cools the fi re, mak-
ing it difficult for the tars and gases to ignite, thus creating
dense smoke and poor combustion. This moisture-laden
smoke cools the chimney, compounding the problem by
offering the smoke the ideal place to condense.
In summary, a certain amount of creosote is inevitable
and must be lived with. Regular inspection and cleaning is
the solution. The use of dry, seasoned wood and ample
combustion air will help to minimize the buildup.
Chimney Fires
The result of excessive creosote buildup is a chimney
fi re. Chimney fi res are dangerous. Chimney inside
temperatures can exceed 2000° F. This causes much
higher than normal temperatures in the chimney and on
its exterior surfaces. Thus ignition of nearby or touching
combustible material is more likely during a chimney fi re.
Proper clearances are critical during such a fi re.
Chimney fi res are easy to detect; they usually involve one
or more of the following:
-Flames and sparks shooting out of the top of the
chimney
-A roaring sound
-Vibration of the chimney
In Case of a Chimney Fire
1. Have a fi re extinguisher handy. Contact your local
municipal or provincial fi re authority for further information
on how to handle a chimney fi re. It is most important that
you have a clearly understood plan on how to handle a
chimney fi re.
2. Close air inlet on stove.
3. Call local fi re department.
4 Prepare to evacuate to ensure everyone's safety. Have
a well understood plan of action for evacuation. Have a
place outside where everyone is to meet.
5. After the chimney fi re is out, the chimney must be
cleaned and checked for stress and cracks before
starting another fi re. Also check combustibles around
the chimney and the roof. The services of a competent
or certifi ed installer,
(certifi ed by the Wood Energy
Technical Training program (WETT) - in Canada, Hearth
Education Foundation (HEARTH) - in U.S.A.,) are strongly
recommended.
Avoiding a Chimney Fire
There are two ways to avoid chimney fi res:
1. Do not let creosote build up to a point where a chimney
fi re is possible.
2. Do not have fi res in the heater that may ignite chimney
fi res. These are hot fi res, such as when burning household
trash, cardboard, Christmas tree limbs, or even ordinary
fuel wood; (e.g.. with a full load on a hot bed of coals and
with the air inlet excessively open.)
3. The Chimney connector pipe should be disconnected
from stove to clean and inspect the chimney. Only if this
is not possible should you remove baffle assembly
